Olefin polymerization catalysts are of great use in industry. Hence there is interest in finding new catalyst systems, including catalyst activators that increase the polymerization activity of the catalyst and allow the production of polymers having specific properties, such as high melting point and high molecular weight.
Catalysts for olefin polymerization are often based on metallocenes as catalyst precursors, which are activated either with the help of an alumoxane, or with an activator containing a non-coordinating anion.
Other references of interest include U.S. Pat. Nos. 5,416,177; 5,817,590; 8,202,958; 8,076,419; 7,531,605; 7,741,417, 6,355,747; 7,851,644; 7,081,543; 6,342,566; 6,960,676; 6,384,142; 6,472,474; U.S. Patent Publication Nos. 2011/0172375 and 2010/0152388; EP Patent Publication Nos. 0 277 004, 0 405 201, 0 798 306, 0 630 910; PCT Publication Nos. WO 91/02012, WO 01/62764, WO 01/68718, WO 2004/005360, WO 01/48035, WO 03/035708; M. A. Giardello, M. S. Eisen, Ch. L. Stern and T. J. Marks, J. Am. Chem. Soc. 1995, 117, pp. 12114-12129; and E. A. Sanginov, A. N. Panin, S. L. Saratovskikh, N. M. Bravaya, Polymer Science, Series A (2006), 48(2), pp. 99-106.
There is still a need in the art for new and improved catalyst systems for the polymerization of olefins, in order to achieve specific polymer properties, such as high melting point, high molecular weights, to increase conversion or comonomer incorporation, or to alter comonomer distribution without deteriorating the resulting polymer's properties.
It is therefore an object of the present invention to provide novel catalyst compounds, catalysts systems comprising such compounds, and processes for the polymerization of olefins using such compounds and systems.